Evolution to alternative levels of stable diversity leaves areas of niche space unexplored
Fig 10
Finite population size can cause transitions in level of diversity due to demographic stochasticity.
This simulation was run using the quartic carrying capacity, Gaussian mutation with σmut = 0.005, Kmax = 200, and initiated with 89 randomly placed individuals. Panel A displays the number of phenotypic clusters over time. Panel B shows the complete history of evolutionary dynamics, with the x-axis representing phenotype z1 and color representing phenotype z2 (red = -2, white = 0, blue = 2). A transition between diversity states due to a stochastic extinction event can be seen approximately around time = 70000. Panel C is a depiction of the population at the end of the simulation (individuals shown as points). Colors in panel C represent the invasion fitness (measured as the birth rate—death rate of a new mutant). Positive invasion fitness is shown in shades of orange, negative in blue, and invasion fitness equal to zero in white.